web browser that uses these APIs. This is because the internal resampler, which is no longer configurable, defaults to a fast integer-based linear interpolation (e.g. new sample is taken as an exact duplicate of the nearest sample instead of a varying portion of the two nearest samples), which was the lowest-quality conversion mode that could be set in previous versions of Windows. The resampler can be set to a high-quality mode via a hotfix for Windows 7 and Windows Server 2008 only. Audio Compression Manager Audio Compression Manager (ACM) is a Windows multimedia framework that manages audio codecs (compressor/decompressors). ACM can also be considered an API specification. A codec must conform to the implicit ACM specification to work with Windows Multimedia. ACM files can be recognized by their filename extension .acm. ACM files also use RIFF-compatible filetypes such as WAV or AVI as a "wrapper" to store audio data encoded by any audio codec supported by ACM. ACM is considered an outdated framework/API and Microsoft now encourages the use of at least DirectShow. However, unlike ACM and the related Video Compression Manager (VCM), DirectShow provides no means to encode files for end-users but requires developers to build end-to-end graphs for encoding content. ACM also does not support VBR audio streams; therefore newer codecs like MPEG-4 AAC, Ogg Vorbis, FLAC etc. cannot be supported through ACM if using variable bitrates. Though many sources state the contrary, Ogg Vorbis does work well with the ACM, e.g. when embedded in a RIFF-compatible file (such as a WAV or AVI file as mentioned earlier), provided the Ogg Vorbis stream is encoded at a constant bitrate. Windows comes with a number of ACM codecs pre-installed. For a list of these codecs, consult . ACM codecs are identified by a two-byte code (TwoCC) allocated by Microsoft. DirectX Audio Libraries DirectSound DirectMusic DirectX plugin KMixer KMixer is the Kernel Audio Mixer driver, a part of WDM Audio in Windows 98 to Windows XP which handles the mixing of multiple sound buffers into an output. The tasks performed by KMixer.sys: Mixing multiple PCM audio streams Format, bit-depth (also known as word-length) and sample-rate conversion Speaker configuration and channel mapping In Windows 98, Windows 2000 and Windows Me, the KMixer maximum sample rate is 100 kHz. In Windows XP SP1 and later, KMixer audio sampling rate supports a maximum of 200 kHz. Issues The KMixer was designed to aid